Profit per piece:160-125.4985 = 34.38+05.

Yield: 34.5015/125.4985 = 27.4916% is consistent with the exchange rate you calculated, that is,1.67/6.08 = 27.4916.

Reply: 10000/ unit cost =10000/125.4985 = 79.68223 items.

Total profit: 79.68223x160-10000 = 2749.438+06.

Profit rate: 2749.16/10000 = 27.4438+06%.

These two algorithms are consistent.

Your question is how high the exchange rate is, and the profit rate is really calculated later.